Method, apparatus and system for monitoring ultra-high frequency partial discharge of hydro-generator

Abstract

The present disclosure provides a method, apparatus and system for monitoring ultra-high frequency partial discharge of a hydro-generator, and belongs to the technical field of hydro-generator partial discharge monitoring. The method includes: cleaning a partial discharge pulse sequence using a cleaning threshold to obtain a valid pulse sequence; performing redundant data filtering on each data unit divided from the valid pulse sequence to obtain a first target pulse sequence for short-period partial discharge monitoring; determining sub-sequences that are partial discharge events from the valid pulse sequence, forming a second target pulse sequence after associating an amplitude statistical feature of the sub-sequences, and storing the second target pulse sequence. The aforementioned method combines data cleaning, redundant data filtering, and partial discharge event identification, which enhances the real-time performance of partial discharge monitoring and records the long-period partial discharge change trend. The corresponding system adopts a multi-buffer zone and multi-processor architecture, thus further improving the real-time performance of partial discharge monitoring.

1 . A method for monitoring ultra-high frequency partial discharge of a hydro-generator, comprising:
 acquiring a partial discharge pulse sequence generated after analog-to-digital conversion of a partial discharge signal of the hydro-generator;   determining a cleaning threshold based on amplitude distribution of the partial discharge pulse sequence, and cleaning the partial discharge pulse sequence using the cleaning threshold to obtain a valid pulse sequence;   performing redundant data filtering on each data unit divided from the valid pulse sequence to obtain a first target pulse sequence for short-period partial discharge monitoring;   dividing the valid pulse sequence into a plurality of sub-sequences, and determining the sub-sequences that are partial discharge events from the plurality of sub-sequences based on a characteristic of repeated occurrences of a partial discharge value of a same insulation defect, forming a second target pulse sequence with the sub-sequences determined to be the partial discharge events, wherein the second target pulse sequence is configured to perform long-period partial discharge change trend analysis, and the inside of the second target pulse sequence is labelled with an amplitude statistical feature of the internal sub-sequences thereof; and   storing the second target pulse sequence.   
     
     
         2 . The method of  claim 1 , wherein obtaining the valid pulse sequence comprises:
 dividing the partial discharge pulse sequence into a plurality of data units at preset time interval, the preset time interval being greater than a time width of at least one partial discharge signal, and each data unit being labeled with an amplitude accumulation feature of an internal partial discharge pulse thereof; and   determining a cleaning threshold based on the amplitude accumulation feature of the data unit, and using the cleaning threshold to clean the partial discharge pulse sequence to obtain a valid pulse sequence.   
     
     
         3 . The method of  claim 2 , wherein the preset time interval is 1 μs. 
     
     
         4 . The method of  claim 2 , wherein obtaining the valid pulse sequence further comprises:
 determining a cleaning threshold based on the amplitude accumulation feature of the data unit;   adding a state value label of 1 to the data unit if the amplitude accumulation feature of the data unit is greater than or equal to the cleaning threshold, otherwise adding a state value label of 0 to the data unit; and   removing the data units with the state value label of 0 and forming a valid pulse sequence by the data units with the state value label of 1.   
     
     
         5 . The method of  claim 2 , wherein determining the sub-sequences that are partial discharge events from the plurality of sub-sequences comprises:
 comparing the amplitude accumulation feature of each data unit in the sub-sequence to an absolute threshold, and determining that the sub-sequence is a partial discharge event if the number of data units whose amplitude accumulation feature exceeds the absolute threshold is greater than a first predetermined value.   
     
     
         6 . The method of  claim 2 , wherein the amplitude accumulation feature is a mean value of amplitudes of partial discharge pulses within the corresponding data unit, or the amplitude statistical feature comprises at least one of a maximum value and an average value of the amplitude accumulation feature within the corresponding sub-sequence. 
     
     
         7 . The method of  claim 1 , wherein the redundant data filtering comprises:
 sorting internal partial discharge pulse amplitudes in a descending order for each data unit divided from the valid pulse sequence, and forming a first target pulse sequence by pulse sequences corresponding to top j partial discharge pulse amplitudes within each data unit, wherein, j≤X, X is the maximum number of pulses reserved in each data unit.   
     
     
         8 . An apparatus for monitoring ultra-high frequency partial discharge of a hydro-generator, comprising:
 a data cleaning processor, configured to determine a cleaning threshold based on amplitude distribution of a partial discharge pulse sequence collected by an ultra-high frequency partial discharge sensor, and clean the partial discharge pulse sequence based on the cleaning threshold to obtain a valid pulse sequence;   a data synthesis processor, configured to perform redundant data filtering on each data unit divided from the valid pulse sequence to obtain a first target pulse sequence for short-period partial discharge monitoring; divide the valid pulse sequence into a plurality of sub-sequences, determine the sub-sequences that are partial discharge events from the plurality of sub-sequences based on the characteristic of repeated occurrences of a partial discharge value of a same insulation defect, and form a second target pulse sequence with the sub-sequences determined to be the partial discharge events so as to perform long-period partial discharge change trend analysis; and   a data storage processor, configured to control a memory connected to the data storage processor to store the second target pulse sequence.   
     
     
         9 . The apparatus of  claim 8 , wherein the apparatus further comprises a coordination control processor and a data labeling processor;
 the coordination control processor is configured to: coordinate and control functional execution of each processor; coordinate and control data transmission between any two of the processors and a host computer; in response to a partial discharge monitoring operation instruction sent by the host computer, establish timing tasks, wherein each timing task occupies a continuous time period, and within each timing task, sequentially execute preprocessing control, classification and labeling control, and transmission control for a partial discharge signal;   the data cleaning processor is further configured to: receive the partial discharge signal and preprocess the partial discharge signal based on a preprocessing instruction issued by the coordination control processor within the current timing task to obtain a first data unit, the first data unit comprising the partial discharge pulse sequence;   the data labeling processor is configured to: apply a label characterizing a partial discharge statistical feature to the first data unit based on a classification and labeling instruction issued by the coordination control processor within the current timing task, when the first data unit triggers a threshold condition of the partial discharge event, apply a label characterizing partial discharge event feature information to the current partial discharge event, after labeling, transmit the labeled first data unit to the host computer based on a transmission control instruction issued by the coordination control processor within the current timing task to enable the host computer to perform partial discharge change trend analysis, and transmit the labeled partial discharge event to the data storage processor; and   the data storage processor is further configured to store the labeled partial discharge event in the memory.   
     
     
         10 . The apparatus of  claim 9 , wherein the label characterizing the partial discharge statistical feature comprises a maximum partial discharge value, or the label characterizing the partial discharge event feature information comprises a partial discharge value, a phase, and a time of occurrence of the partial discharge event. 
     
     
         11 . The apparatus of  claim 9 , wherein the data labeling processor comprises a monitoring data buffer zone and a storage data buffer zone;
 the monitoring data buffer zone is configured to write a first data unit output from the data cleaning processor, and the data labeling processor reads the first data unit from the monitoring data buffer zone upon applying a label characterizing a partial discharge statistical feature to the first data unit based on a classification and labelling instruction issued by the coordination control processor within the current timing task;   the storage data buffer zone is configured to write a first data unit output from the data cleaning processor, the data labeling processor determines the partial discharge event from the first data unit read from the storage data buffer zone upon applying a label characterizing partial discharge event feature information to the current partial discharge event based on a classification and labelling instruction issued by the coordination control processor within the current timing task;   wherein, the monitoring data buffer zone comprises a first buffer zone and a second buffer zone, the first buffer zone and the second buffer zone share a read pointer and a write pointer, the direction of the write pointer and the direction of the read pointer are both switched between the first buffer zone and the second buffer zone during the switching of timing tasks; and   wherein, the storage data buffer zone comprises a third buffer zone and a fourth buffer zone, the third buffer zone and the fourth buffer zone share a read pointer and a write pointer, and the direction of the write pointer and the direction of the read pointer are both switched between the third buffer zone and the fourth buffer zone during the switching of timing tasks.   
     
     
         12 . The apparatus of  claim 9 , wherein a continuous time period occupied by each timing task is provided with a dormancy period. 
     
     
         13 . The apparatus of  claim 9 , wherein the timing task is divided into two tiers, the first tier of the timing task executes sampling control, transmission control and bus control on the partial discharge signal in a timing sequence, a second tier of the timing task is configured to issue a link establishment instruction, a display communication setup instruction and a data display instruction under bus control and a data cleaning instruction, a classification and labeling instruction and a data caching instruction under sampling control when the timing task is executed;
 the data cleaning processor is configured to, within the current timing task, perform analog-to-digital conversion on the partial discharge signal based on a sampling control instruction issued by the sampling control to obtain a partial discharge pulse sequence, and after analog-to-digital conversion, perform data cleaning on the partial discharge pulse sequence based on a data cleaning instruction to obtain a first data unit;   the data labeling processor is configured to, within the current timing task:
 write the first data unit to the monitoring data buffer zone and the storage data buffer zone based on the data caching instruction, then read the first data unit cached within the monitoring data buffer zone based on the classification and labeling instruction, apply a label characterizing a partial discharge statistical feature to the first data unit, and read the first data unit cached within the storage data buffer zone based on the classification and labeling instruction, and apply a label characterizing partial discharge event feature information to the current partial discharge event when the first data unit triggers a threshold condition for the partial discharge event; 
 perform data preparation for the labeled first data unit to be transmitted and the labeled partial discharge event based on the transmission control instruction; 
 establish a PCIE bus transmission link with the host computer and the data storage processor via an internal bus interface circuit inside based on the link establishment instruction; 
 establish communication with the host computer via a data display interface circuit inside based on the display communication setup instruction; and 
 transmit, via a data display interface circuit, the labeled first data unit to the host computer for partial discharge change trend analysis and display based on the data display instruction. 
   
     
     
         14 . The apparatus of  claim 9 , wherein the coordination control processor is further configured to:
 perform initialization and hardware drive loading in response to the partial discharge monitoring operation instruction of the host computer;   establish timing tasks, the timing task being divided into two tiers, each timing task occupying one continuous time period, and one continuous time period being denoted as t k ˜t p , wherein, t k  denotes a starting moment of partial discharge signal preprocessing, t p  denotes the moment when the labeled first data unit is displayed by the host computer, t 1 , t 2  and t 3 , in turn, are three moments within the continuous time period from t k  to t p , and t 1 <t 2 <t 3 , the first tier of timing task is executed in a timing sequence, within one timing task, sampling control, transmission control and bus control are executed on the partial discharge signal in sequence, the second tier of the timing task is configured to issue a link establishment instruction, a display communication setup instruction and a data display instruction under bus control and a data cleaning instruction, a classification and labeling instruction and a data caching instruction under sampling control when the timing task is executed;   during the time period of t k ˜t 1 , issue a sampling control instruction to a data cleaning processor to enable the data cleaning processor to perform analog-to-digital conversion on the partial discharge signal based on the sampling control instruction to obtain the partial discharge pulse sequence, after analog-to-digital conversion, issue a data cleaning instruction to the data cleaning processor to enable the data cleaning processor to perform data cleaning on the partial discharge pulse sequence based on the data cleaning instruction to obtain the first data unit, and issue a data caching instruction to the data labeling processor to enable the data labeling processor to write the first data unit into the monitoring data buffer zone and the storage data buffer zone inside based on the data caching instruction;   during the time period of t 1 ˜t 2 , issue the classification and labeling instruction to the data labeling processor to enable the data labeling processor to read the first data unit cached within the monitoring data buffer zone based on the classification and labeling instruction, and apply to the first data unit a label characterizing the partial discharge statistical feature, and read the first data unit cached within the storage data buffer zone based on the classification and labeling instruction, and when the first data unit triggers a threshold condition for a partial discharge event, apply a label characterizing partial discharge event feature information to the current partial discharge event to enable the data storage processor to receive the labeled partial discharge event and control the memory to store the partial discharge event;   at the t 2  moment, issue a transmission control instruction to the data labeling processor to enable the data labeling processor to perform data preparation for the labeled first data unit to be transmitted and the labeled partial discharge event;   at the t 2  moment, issue a link establishment instruction to the data labeling processor to enable establishment of a PCIE bus transmission link with the host computer and the data storage processor via a bus interface circuit in the data labeling processor;   at the t 2  moment, issue a display communication establishment instruction to the data labeling processor to establish communication with the host computer via a data display interface circuit in the data labeling processor;   during the time period of t 2 ˜t 3 , perform dormancy; and   during the time period of t 3 ˜t p , issue a data display instruction to the data labeling processor to facilitate sending the labeled first data unit to the host computer via the data display interface circuit for partial discharge change trend analysis and display.   
     
     
         15 . The apparatus of  claim 8 , wherein in the data synthesis processor, a first task of obtaining the first target pulse sequence and a second task of obtaining the second target pulse sequence are executed in parallel, and the parallel execution comprises writing the valid pulse sequence from the first data buffer zone and the second data buffer zone in which the valid pulse sequence is stored, respectively, for data processing. 
     
     
         16 . The apparatus of  claim 15 , wherein the first data buffer zone comprises a buffer zone A and a buffer zone B; the valid pulse sequence is stored in the buffer zone A, and when the buffer zone A is full, a write data interface is switched to the buffer zone B, while the data synthesis processor reads data from the buffer zone A; and
 the second data buffer zone comprises a buffer zone C and a buffer zone D; the valid pulse sequence is stored in the buffer zone C, and when the buffer zone C is full, the write data interface is switched to the buffer zone D, while the data synthesis processor reads data from the buffer zone C.   
     
     
         17 . A system for monitoring ultra-high frequency partial discharge of a hydro-generator, wherein the system comprises:
 an ultra-high frequency partial discharge sensor, mounted on a stator winding of the hydro-generator, configured to collect a partial discharge signal of the hydro-generator;   an analog-to-digital converter, configured to perform analog-to-digital conversion on the partial discharge signal to generate a partial discharge pulse sequence;   the apparatus of  claim 9 , configured to perform data cleaning, data processing and data storage on the partial discharge pulse sequence to obtain a first target pulse sequence for short-period partial discharge monitoring and a second target pulse sequence for long-period partial discharge change trend analysis, and configured to label a partial discharge event;   a host computer, configured to perform short-period partial discharge monitoring after acquiring the first target pulse sequence; and   a memory, configured to store the labeled partial discharge event.   
     
     
         18 . The system of  claim 17 , wherein for the apparatus, the data synthesis processor and the data labeling processor are communicatively connected with the data storage processor and the host computer, respectively, via a PCIE bus.